Due to the gradual slowdown in Earth's rotation, a team at the Paris Observatory is adding a "leap second" just before
midnight. Experts
at the International Earth Rotation and Reference System Service make
the adjustment when the planet's movement falls out of sync with atomic
clocks used to measure time.
"Today, time is constructed defined and
measured with atomic clocks" said Noel Dimarcq, director of the SYRTE
time-space reference system at the Paris Observatory. "This allows us to ensure that everyone on Earth is on the exact same time," Daily Mail quoted Dimarcq as saying.
Today's final minute (Greenwich Time), with its added second, will compensate
for the sloshing of oceanic tides on the continental shelves, which
slows Earth's rotation ever so slightly. It's been four years since a leap second has been added.
Saturday, June 30, 2012
Wednesday, June 20, 2012
Closure of 70 of California's State Parks
The First 70 Trailer from Heath Hen Films on Vimeo.
On July 1st, up to 70 of California’s 279 state parks may be closed due to budget cuts enacted by the Governor and Legislature. This closure will affect 25% of California's beautiful parks will erode the state’s commitment and legacy to irreplaceable natural, cultural, and historic resources. Additionally, closing state parks will impact California’s travel and tourism industry and reduce much-needed revenues for local businesses. As the parks are shut down they will no longer be considered in the state's eyes as an asset, which will allow for lobbyists to push to have state protection of the parks removed. This will allow for timber, mining, and real estate interests to purchase bits of the parks. Although this will profit them immensely, it will devastate the national landmarks and leave the land ravaged.
Labels:
California,
forest,
mining,
state parks,
timber,
trees,
video
Monday, June 4, 2012
Transit of Venus!
There
will
be
a
"transit
of
Venus"
on
Tuesday,
June
5,
visible
from
throughout
the
USA.
(It
will
occur
on
June
6
in
Asia,
across
the
International
Date
Line.)
Venus
will
look
like
a
tiny
black
dot
on
the
Sun.
The
last
time
this
occurred
was
in
June
2004.
After
June
5,
2012,
to
see
the
transit
of
Venus
anywhere
on
Earth
you'll
need
to
wait
until
the
year
2117,
and
then
2125
–
no
kidding!
(The
previous
pair
of
Venus
transits
was
in
1874
and
1882.)
So,
I
suggest
you
see
it!
A transit of Venus occurs when Venus passes right between Earth and the Sun: it looks like a tiny black dot, about 1/30th the size of the Sun (more technically, about 1 arcminute in diameter), slowly going across the Sun. You'll be able to just barely see it with the unaided (but protected) eye, but a far better, magnified image will be visible if you look through binoculars (properly filtered) or a telescope (again, properly filtered). If you wish, you can get very nice, appropriate equipment at many stores, such as Scope City. Wherever you live, local amateur astronomy organizations and science centers will set up telescopes for public viewing, you'll just have to check online for locations. The Chabot Space and Science Centerin the Oakland hills is one such example.
In the Pacific Daylight Time (PDT) zone, the transit starts on June 5 at about 3:07 pm, though it will be hard to notice until around 3:24 pm. Mid-eclipse will be at 6:27 pm. In the San Francisco Bay Area, sunset occurs around 8:28 pm. The transit ends at 9:47 pm PDT, after sunset in California. As with the partial lunar eclipse above, if you are in other time zones, adjust the times accordingly. These times are, of course, approximate to within a few minutes, however they will depend slightly on your exact location within a time zone. So, progressively less of the transit will be visible the farther east you go in the USA.
Suppose you consider the Sun’s disk to be like the face of a clock when you look directly at it. As seen from San Francisco and most of the USA/Canada, Venus will begin to transit at roughly the 12 o’clock position (i.e., near the top of the Sun), but around sunset, Venus will be near the 4 o’clock position. More information on the event can be found at transitofvenus.org, and eclipse.gsfc.nasa.gov/OH/transit12.html.
Transits of Venus are historically important because observations of them in 1761 and 1769 from many different locations on Earth led to the first accurate (to within 2%) estimate of Earth's distance from Venus, and hence of Earth’s distance from the Sun (the “Astronomical Unit”) since the relative distances were already known. Viewed from a given location on Earth, the exact position of Venus’s silhouette depends on Venus’s distance, so one can solve for the distance using a bunch of measurements. Transits of Venus are important now because they illustrate the technique with which thousands of exoplanets are being found by the Kepler spacecraft: the total brightness of a star periodically drops a tiny bit while an exoplanet transits across its disk, as seen by us. If you monitor a star’s brightness and notice a slight periodic dimming, you’ve probably detected an exoplanet.
If you are planning on looking directly at the Sun, remember that you need proper eye protection or you could permanently damage your eyes! Use "Shade 14 welder's glass" (available at welding supply stores) or some other safe filter which blocks 99.999% of the Sun's rays at visible, ultraviolet, and infrared wavelengths. Appropriate "eclipse glasses" can also be found and purchased online for just a few dollars (comparable to Shade 14 welder's glass, but less durable). Regular sunglasses or smoked glass won't suffice by a long shot.
Without magnification, the black silhouette of Venus will be barely visible to the naked eye, or possibly even invisible, depending on your visual acuity. A magnified view will be much better. If you have a sufficiently small pair of binoculars, you can securely tape a piece of Shade 14 glass across the front end (so that light goes through the filter before entering the binoculars). Many local amateur astronomy clubs and science centers will have properly filtered telescopes for public viewing, providing a magnified image. I encourage you to visit them and watch the transit safely.
Source: culture-and-current-affairs.com
A transit of Venus occurs when Venus passes right between Earth and the Sun: it looks like a tiny black dot, about 1/30th the size of the Sun (more technically, about 1 arcminute in diameter), slowly going across the Sun. You'll be able to just barely see it with the unaided (but protected) eye, but a far better, magnified image will be visible if you look through binoculars (properly filtered) or a telescope (again, properly filtered). If you wish, you can get very nice, appropriate equipment at many stores, such as Scope City. Wherever you live, local amateur astronomy organizations and science centers will set up telescopes for public viewing, you'll just have to check online for locations. The Chabot Space and Science Centerin the Oakland hills is one such example.
In the Pacific Daylight Time (PDT) zone, the transit starts on June 5 at about 3:07 pm, though it will be hard to notice until around 3:24 pm. Mid-eclipse will be at 6:27 pm. In the San Francisco Bay Area, sunset occurs around 8:28 pm. The transit ends at 9:47 pm PDT, after sunset in California. As with the partial lunar eclipse above, if you are in other time zones, adjust the times accordingly. These times are, of course, approximate to within a few minutes, however they will depend slightly on your exact location within a time zone. So, progressively less of the transit will be visible the farther east you go in the USA.
Suppose you consider the Sun’s disk to be like the face of a clock when you look directly at it. As seen from San Francisco and most of the USA/Canada, Venus will begin to transit at roughly the 12 o’clock position (i.e., near the top of the Sun), but around sunset, Venus will be near the 4 o’clock position. More information on the event can be found at transitofvenus.org, and eclipse.gsfc.nasa.gov/OH/transit12.html.
Transits of Venus are historically important because observations of them in 1761 and 1769 from many different locations on Earth led to the first accurate (to within 2%) estimate of Earth's distance from Venus, and hence of Earth’s distance from the Sun (the “Astronomical Unit”) since the relative distances were already known. Viewed from a given location on Earth, the exact position of Venus’s silhouette depends on Venus’s distance, so one can solve for the distance using a bunch of measurements. Transits of Venus are important now because they illustrate the technique with which thousands of exoplanets are being found by the Kepler spacecraft: the total brightness of a star periodically drops a tiny bit while an exoplanet transits across its disk, as seen by us. If you monitor a star’s brightness and notice a slight periodic dimming, you’ve probably detected an exoplanet.
If you are planning on looking directly at the Sun, remember that you need proper eye protection or you could permanently damage your eyes! Use "Shade 14 welder's glass" (available at welding supply stores) or some other safe filter which blocks 99.999% of the Sun's rays at visible, ultraviolet, and infrared wavelengths. Appropriate "eclipse glasses" can also be found and purchased online for just a few dollars (comparable to Shade 14 welder's glass, but less durable). Regular sunglasses or smoked glass won't suffice by a long shot.
Without magnification, the black silhouette of Venus will be barely visible to the naked eye, or possibly even invisible, depending on your visual acuity. A magnified view will be much better. If you have a sufficiently small pair of binoculars, you can securely tape a piece of Shade 14 glass across the front end (so that light goes through the filter before entering the binoculars). Many local amateur astronomy clubs and science centers will have properly filtered telescopes for public viewing, providing a magnified image. I encourage you to visit them and watch the transit safely.
Saturday, June 2, 2012
Upcoming Partial Lunar Eclipse
On
the
morning
of
Monday,
June
4,
there
will
be
a
partial
eclipse
of
the
full
moon
in
the
few
hours
before
sunrise.
About
a
third
of
the
Moon
will
enter
the
Earth’s
dark
shadow,
starting
at
3:00
am
PDT
and
ending
at
5:06
am
PDT
(mid-‐eclipse
at
4:03
am
PDT).
No
optical
aid
is
needed
to
view
the
eclipse,
though
binoculars
or
telescopes
will
provide
a
magnified
view.
There
is
no
danger
when
viewing
a
lunar
eclipse
with
the
naked
eye,
binoculars,
or
telescopes;
filters
are
not
needed
(unlike
the
case
for
a
partial
solar
eclipse).
Just
go
outside
wherever
you
are,
and
take
a
look!
But
some
local
astronomy
clubs
and
science
centers
(such
as
the
Chabot Space and Science Center in
the
Oakland
hills)
will
hold
official
public
viewing
sessions;
check
online.
The entire easily visible part of the eclipse (when the Moon is in the Earth’s “umbra,” or full shadow) will be visible from California. As seen from the central USA, moonset will occur during the eclipse. The eastern US will basically miss out on this eclipse, since it will begin around or after moonset. West of California (say, in Hawaii), the entire eclipse [penumbra (partial, bright shadow) and umbra (full, dark shadow)] will be visible with the Moon high in the sky. For more information, see http://eclipse.gsfc.nasa.gov/OH/OH2012.html#LE2012Jun04P (courtesy of Fred Espenak, NASA’s GSFC.
The entire easily visible part of the eclipse (when the Moon is in the Earth’s “umbra,” or full shadow) will be visible from California. As seen from the central USA, moonset will occur during the eclipse. The eastern US will basically miss out on this eclipse, since it will begin around or after moonset. West of California (say, in Hawaii), the entire eclipse [penumbra (partial, bright shadow) and umbra (full, dark shadow)] will be visible with the Moon high in the sky. For more information, see http://eclipse.gsfc.nasa.gov/OH/OH2012.html#LE2012Jun04P (courtesy of Fred Espenak, NASA’s GSFC.
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